1. Technical Field
The present invention relates to an antireflection article, a polarizing plate, a cover glass and an image display device, and a manufacturing method of an antireflection article.
2. Related Art
In an image display device such as a cathode ray tube display device (CRT), a plasma display panel (PDP), an electroluminescent display (ELD), a vacuum fluorescent display (VFD), a field emission display (FED), and a liquid crystal display (LCD), an antireflection film may be provided in some cases in order to prevent a reduction in contrast or glare of an image due to reflection of external light on a display surface of the device. Further, it is possible to impart an antireflection function by an antireflection film in addition to an image display device in some cases.
As the antireflection film, there has been known an antireflection film having a fine unevenness shape on a surface of a substrate, of which a period is equal to or shorter than the wavelengths of visible rays, so-called an antireflection film having a moth eye structure. Due to the moth eye structure, a refractive index gradient layer in which a refractive index is continuously varied from air toward a bulk material at an inside of the substrate is artificially formed, so that light may be prevented from being reflected.
As an antireflection layer having a moth eye structure, Japanese Patent Laid-Open Publication No. 7-104103 describes an antireflection film having an unevenness structure, manufactured by removing a binder resin which contains particles formed on a plastic film substrate while remaining the back part of the particles by means of dry etching.
However, it has been found that for the antireflection film described in Japanese Patent Laid-Open Publication No. 7-104103, during black display when used on a surface of a display, or when used on a surface of glass in a dark showroom, and the like, a blue tint resulting from the wavelength dependence of reflectance is generated.
An object of the present invention is to provide an antireflection article having a moth eye structure on a surface thereof, in which the reflectance is low and a blue tint is also suppressed from being generated. In addition, another object of the present invention is to provide a polarizing plate, a cover glass and an image display device, which include the antireflection article, and a manufacturing method of an antireflection article.
The present inventors have reviewed on the generation of the blue tint, and surprisingly, have found that the blue tint may be improved by decreasing an area occupancy ratio of inorganic particles (referred to as a “particle occupancy ratio”) on a surface of an antireflection layer having a moth eye structure. Meanwhile, it has been found that, within a range where the particle occupancy ratio is low, aggregation of the particles is easily generated, and the reflectance is easily increased.
The present inventors have intensively studied and found that the above-described problem can be solved by using, as particles forming a moth eye structure, mono-disperse particles having a CV value of 4% or less, setting the ration of perfectly spherical particles (perfectly spherical particle ratio) to 99.9% or more, and setting the area occupancy ratio of the particles to 25% to 64%.